// Copyright (c) Umbraco.
// See LICENSE for more details.

using System.Collections;
using System.Collections.Concurrent;
using System.Collections.Specialized;
using System.Net;
using System.Text;
using Umbraco.Cms.Core;

namespace Umbraco.Extensions;

/// <summary>
///     Extension methods for Dictionary &amp; ConcurrentDictionary.
/// </summary>
public static class DictionaryExtensions
{
    /// <summary>
    ///     Method to Get a value by the key. If the key doesn't exist it will create a new TVal object for the key and return
    ///     it.
    /// </summary>
    /// <typeparam name="TKey"></typeparam>
    /// <typeparam name="TVal"></typeparam>
    /// <param name="dict"></param>
    /// <param name="key"></param>
    /// <returns></returns>
    public static TVal GetOrCreate<TKey, TVal>(this IDictionary<TKey, TVal> dict, TKey key)
        where TVal : class, new()
    {
        if (dict.TryGetValue(key, out TVal? existing))
        {
            return existing;
        }

        TVal value = new();
        dict.Add(key, value);
        return value;
    }

    /// <summary>
    ///     Updates an item with the specified key with the specified value
    /// </summary>
    /// <typeparam name="TKey"></typeparam>
    /// <typeparam name="TValue"></typeparam>
    /// <param name="dict"></param>
    /// <param name="key"></param>
    /// <param name="updateFactory"></param>
    /// <returns></returns>
    /// <remarks>
    ///     Taken from:
    ///     http://stackoverflow.com/questions/12240219/is-there-a-way-to-use-concurrentdictionary-tryupdate-with-a-lambda-expression
    ///     If there is an item in the dictionary with the key, it will keep trying to update it until it can
    /// </remarks>
    public static bool TryUpdate<TKey, TValue>(this ConcurrentDictionary<TKey, TValue> dict, TKey key, Func<TValue, TValue> updateFactory)
        where TKey : notnull
    {
        while (dict.TryGetValue(key, out TValue? curValue))
        {
            if (dict.TryUpdate(key, updateFactory(curValue), curValue))
            {
                return true;
            }

            // if we're looping either the key was removed by another thread, or another thread
            // changed the value, so we start again.
        }

        return false;
    }

    /// <summary>
    ///     Updates an item with the specified key with the specified value
    /// </summary>
    /// <typeparam name="TKey"></typeparam>
    /// <typeparam name="TValue"></typeparam>
    /// <param name="dict"></param>
    /// <param name="key"></param>
    /// <param name="updateFactory"></param>
    /// <returns></returns>
    /// <remarks>
    ///     Taken from:
    ///     http://stackoverflow.com/questions/12240219/is-there-a-way-to-use-concurrentdictionary-tryupdate-with-a-lambda-expression
    ///     WARNING: If the value changes after we've retrieved it, then the item will not be updated
    /// </remarks>
    public static bool TryUpdateOptimisitic<TKey, TValue>(this ConcurrentDictionary<TKey, TValue> dict, TKey key, Func<TValue, TValue> updateFactory)
        where TKey : notnull
    {
        if (!dict.TryGetValue(key, out TValue? curValue))
        {
            return false;
        }

        dict.TryUpdate(key, updateFactory(curValue), curValue);
        return true; // note we return true whether we succeed or not, see explanation below.
    }

    /// <summary>
    ///     Converts a dictionary to another type by only using direct casting
    /// </summary>
    /// <typeparam name="TKeyOut"></typeparam>
    /// <typeparam name="TValOut"></typeparam>
    /// <param name="d"></param>
    /// <returns></returns>
    public static IDictionary<TKeyOut, TValOut> ConvertTo<TKeyOut, TValOut>(this IDictionary d)
        where TKeyOut : notnull
    {
        var result = new Dictionary<TKeyOut, TValOut>();
        foreach (DictionaryEntry v in d)
        {
            result.Add((TKeyOut)v.Key, (TValOut)v.Value!);
        }

        return result;
    }

    /// <summary>
    ///     Converts a dictionary to another type using the specified converters
    /// </summary>
    /// <typeparam name="TKeyOut"></typeparam>
    /// <typeparam name="TValOut"></typeparam>
    /// <param name="d"></param>
    /// <param name="keyConverter"></param>
    /// <param name="valConverter"></param>
    /// <returns></returns>
    public static IDictionary<TKeyOut, TValOut> ConvertTo<TKeyOut, TValOut>(
        this IDictionary d,
        Func<object, TKeyOut> keyConverter,
        Func<object, TValOut> valConverter)
        where TKeyOut : notnull
    {
        var result = new Dictionary<TKeyOut, TValOut>();
        foreach (DictionaryEntry v in d)
        {
            result.Add(keyConverter(v.Key), valConverter(v.Value!));
        }

        return result;
    }

    /// <summary>
    ///     Converts a dictionary to a NameValueCollection
    /// </summary>
    /// <param name="d"></param>
    /// <returns></returns>
    public static NameValueCollection ToNameValueCollection(this IDictionary<string, string> d)
    {
        var n = new NameValueCollection();
        foreach (KeyValuePair<string, string> i in d)
        {
            n.Add(i.Key, i.Value);
        }

        return n;
    }

    /// <summary>
    ///     Merges all key/values from the sources dictionaries into the destination dictionary
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <typeparam name="TK"></typeparam>
    /// <typeparam name="TV"></typeparam>
    /// <param name="destination">The source dictionary to merge other dictionaries into</param>
    /// <param name="overwrite">
    ///     By default all values will be retained in the destination if the same keys exist in the sources but
    ///     this can changed if overwrite = true, then any key/value found in any of the sources will overwritten in the
    ///     destination. Note that
    ///     it will just use the last found key/value if this is true.
    /// </param>
    /// <param name="sources">The other dictionaries to merge values from</param>
    public static void MergeLeft<T, TK, TV>(this T destination, IEnumerable<IDictionary<TK, TV>> sources, bool overwrite = false)
        where T : IDictionary<TK, TV>
    {
        foreach (KeyValuePair<TK, TV> p in sources.SelectMany(src => src)
                     .Where(p => overwrite || destination.ContainsKey(p.Key) == false))
        {
            destination[p.Key] = p.Value;
        }
    }

    /// <summary>
    ///     Merges all key/values from the sources dictionaries into the destination dictionary
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <typeparam name="TK"></typeparam>
    /// <typeparam name="TV"></typeparam>
    /// <param name="destination">The source dictionary to merge other dictionaries into</param>
    /// <param name="overwrite">
    ///     By default all values will be retained in the destination if the same keys exist in the sources but
    ///     this can changed if overwrite = true, then any key/value found in any of the sources will overwritten in the
    ///     destination. Note that
    ///     it will just use the last found key/value if this is true.
    /// </param>
    /// <param name="source">The other dictionary to merge values from</param>
    public static void MergeLeft<T, TK, TV>(this T destination, IDictionary<TK, TV> source, bool overwrite = false)
        where T : IDictionary<TK, TV> =>
        destination.MergeLeft(new[] { source }, overwrite);

    /// <summary>
    ///     Returns the value of the key value based on the key, if the key is not found, a null value is returned
    /// </summary>
    /// <typeparam name="TKey">The type of the key.</typeparam>
    /// <typeparam name="TVal">The type of the val.</typeparam>
    /// <param name="d">The d.</param>
    /// <param name="key">The key.</param>
    /// <param name="defaultValue">The default value.</param>
    /// <returns></returns>
    public static TVal? GetValue<TKey, TVal>(this IDictionary<TKey, TVal> d, TKey key, TVal? defaultValue = default)
    {
        if (d.TryGetValue(key, out TVal? value))
        {
            return value;
        }

        return defaultValue;
    }

    /// <summary>
    ///     Returns the value of the key value based on the key as it's string value, if the key is not found, then an empty
    ///     string is returned
    /// </summary>
    /// <param name="d"></param>
    /// <param name="key"></param>
    /// <returns></returns>
    public static string? GetValueAsString<TKey, TVal>(this IDictionary<TKey, TVal> d, TKey key)
        => d.TryGetValue(key, out TVal? value) ? value!.ToString() : string.Empty;

    /// <summary>
    ///     Returns the value of the key value based on the key as it's string value, if the key is not found or is an empty
    ///     string, then the provided default value is returned
    /// </summary>
    /// <param name="d"></param>
    /// <param name="key"></param>
    /// <param name="defaultValue"></param>
    /// <returns></returns>
    public static string? GetValueAsString<TKey, TVal>(this IDictionary<TKey, TVal> d, TKey key, string defaultValue)
    {
        if (d.TryGetValue(key, out TVal? dictionaryValue))
        {
            var value = dictionaryValue!.ToString();
            if (value != string.Empty)
            {
                return value;
            }
        }

        return defaultValue;
    }

    /// <summary>contains key ignore case.</summary>
    /// <param name="dictionary">The dictionary.</param>
    /// <param name="key">The key.</param>
    /// <typeparam name="TValue">Value Type</typeparam>
    /// <returns>The contains key ignore case.</returns>
    public static bool ContainsKeyIgnoreCase<TValue>(this IDictionary<string, TValue> dictionary, string key) =>
        dictionary.Keys.InvariantContains(key);

    /// <summary>
    ///     Converts a dictionary object to a query string representation such as:
    ///     firstname=shannon&amp;lastname=deminick.
    /// </summary>
    /// <param name="d"></param>
    /// <returns></returns>
    public static string ToQueryString(this IDictionary<string, object> d)
    {
        if (!d.Any())
        {
            return string.Empty;
        }

        var builder = new StringBuilder();
        foreach (KeyValuePair<string, object> i in d)
        {
            builder.Append(WebUtility.UrlEncode(i.Key));
            builder.Append('=');
            if (i.Value != null)
            {
                builder.Append(WebUtility.UrlEncode(i.Value.ToString()));
            }
            builder.Append('&');
        }

        return builder.ToString().TrimEnd(Constants.CharArrays.Ampersand);
    }

    /// <summary>The get entry ignore case.</summary>
    /// <param name="dictionary">The dictionary.</param>
    /// <param name="key">The key.</param>
    /// <typeparam name="TValue">The type</typeparam>
    /// <returns>The entry</returns>
    public static TValue? GetValueIgnoreCase<TValue>(this IDictionary<string, TValue> dictionary, string key)
        => dictionary!.GetValueIgnoreCase(key, default);

    /// <summary>The get entry ignore case.</summary>
    /// <param name="dictionary">The dictionary.</param>
    /// <param name="key">The key.</param>
    /// <param name="defaultValue">The default value.</param>
    /// <typeparam name="TValue">The type</typeparam>
    /// <returns>The entry</returns>
    public static TValue GetValueIgnoreCase<TValue>(this IDictionary<string, TValue> dictionary, string? key, TValue
        defaultValue)
    {
        key = dictionary.Keys.FirstOrDefault(i => i.InvariantEquals(key));

        return key.IsNullOrWhiteSpace() == false
            ? dictionary[key!]
            : defaultValue;
    }

    public static async Task<Dictionary<TKey, TValue>> ToDictionaryAsync<TInput, TKey, TValue>(
        this IEnumerable<TInput> enumerable,
        Func<TInput, TKey> syncKeySelector,
        Func<TInput, Task<TValue>> asyncValueSelector)
        where TKey : notnull
    {
        var dictionary = new Dictionary<TKey, TValue>();

        foreach (TInput item in enumerable)
        {
            TKey key = syncKeySelector(item);

            TValue value = await asyncValueSelector(item);

            dictionary.Add(key, value);
        }

        return dictionary;
    }
}
